Development of size and shape dependent model for magnetic properties from bulk to nanoscale

A simple model based on the bond energy analysis is developed. The model is used to compute the size and shape dependence of magnetic properties, viz. Curie temperature T-C(D), magnetization M-S(D), and Neel temperature T-N(D), where D denotes the size of nanoparticles. It is found that T-C(D) and M-S(D) decrease with a decrease in size. T-N(D) is found to increase or decrease with dropping D, depending on the interaction strength at the film/substrate interface. The model predictions have been compared with the available experimental data. There is a reasonably good agreement between model predictions and experimental results. The model may be extended to other nanomaterials in different size and shape, due to its simplicity. The results obtained for corresponding bulk material are also included for comparison purposes.